Two populations of human blood basophils: effect of prednisone on circulating numbers.

In a previous study, human blood basophils were separated by centrifugation on Percoll gradients into two fractions, band 1 and band 2, that differed in density and histamine content. In this study, the change in circulating numbers of band 1 and band 2 basophils, as well as other leukocytes, was measured after a single oral dose of prednisone. Three hours after ingestion of 50 mg of prednisone, the circulating number of band 1 basophils was 19 +/- 4% of the preprednisone value, whereas the band 2 level was 87 +/- 18% (SEM for five subjects). At 6 hours, values were 10 +/- 1% and 41 +/- 7% for band 1 and band 2, respectively. Circulating numbers of both basophil populations returned to near normal at 24 hours. The 3-hour response to a 10 mg oral dose in seven subjects was 28 +/- 5% and 89 +/- 10% of preprednisone levels for band 1 and band 2; the 6-hour responses were 28 +/- 7% and 84 +/- 7%. The 3-hour responses of other leukocytes in four of these subjects, expressed as a percentage of preprednisone counts were neutrophils, 171 +/- 27%; lymphocytes, 47 +/- 6%; monocytes, 36 +/- 9%; and eosinophils, 26 +/- 11%. The results demonstrate that band 2 basophils have a lower sensitivity to glucocorticoid action than do band 1 basophils or other types of circulating leukocytes.